Hand-fired furnace



W. S. HOTCHKISS AND J. E. W. SHEEHAN.

HAND FIRED FURNACE.

APPLICATION FILED JUNE3. 1919.

1,397,422, Patented Nov. 15, 1921.

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' HAND FIRED FURNACE.

APPLICATION FILED JUNE 3. 1919.

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HAND FIRED FURNACE.

APPLICATION FILED JUNE 3. I919.

Patented Nov. 15, 1921.

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siren Helm @f f lfilih WILLIAM S. HOTCHKISS AND JOHN E. W. SHEEI-IAN, OF MEMPHIS, TENNESsEE HAND-FIRED FURNACE.

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Application filed. June 3,

T 0 all whom it may concern:

Be it known that we, YVILLIAM S. HoroH- KISS and JOHN E. WV. SI-InnHAN, citizens of the United States of America, residing at Memphis, in the county of Shelby and State of Tennessee, have invented new and useful Improvements in Hand-Fired Furnaces, of which the following is a specification.

The object of the invention is to provide a grate for a furnace of the hand fired type wherein the principles of the forced draft and natural draft shaker grates shall be combined in one structure under such conditions as to utilize the advantages and avoid the disadvantages of both types of grate. It is well recognized that where there are advantages in the use of the forced draft. principle by reason of the more complete combustion of the fuel and the possibility of regulating the draft so as to secure the desired results with reasonable certainty, the necessity of raking the fire bed to remove the ashes and clinkers, and of having the furnace doors open during this operation involves a serious disadvantage, not only in the fact that a reduction of steam pressure is involved during the operation, but owing to the discomfort to which firemen are subjected in performing this service there is a tendency to encourage neglect which results in permitting an undue accumulation of clinkers, and therefore it is desirable to pro vide such a construction of grate as to se cure the advantages of the forced draft without necessitating the frequent removal of the ashes and clinkers, the use of slice bars or the equivalent thereof and hence without exposing the fire bed by the opening of the furnace doors, and without exposing the firemen to the intense heat incidental to such operation; and furthermore and incidentally it is desirable to provide such means for supplying a forced draft as to avoid leakage or waste of pressure, so that accurate calculations may be made to determine the most economical pressures to be used with various kinds of fuel, to the end that the operation of the furnace may be regulated uniformly and economically without in any way impairing the efficiency of the shaker elements by the operation of which the fire bed may be kept free from accumulations of ashes and clinkers, the removal of the former being possible as such intervals as Specification of Letters Patent.

Patented Nov. 15, 11921.. 1919. Serial No. 301,555.

to give no opportunity for reduction to a clinker condition.

lVith these and similar objects in view will appear hereinafter the invention consists in a construction, combination and re lat on of parts of which a preferred embodiment is illustrated in the accompanying drawings, in form, proportion and details mav be resorted to within the scope of the claims wlthout departing from the principles involved.

In the drawing:

Figure l is a plan View of a grate illustrating the combination of the forced draft and shaker features.

Fig. 2 is a side view of a hollow. grate bar and connections constructed as and forming an element of the improved grate.

1* 1g. 3 IS a plan view of one end of a hollow grate bar element, the twyer plate form mg the crown thereof being omitted to show the clean out trap.

Fig. 4 is a longitudinal sectional view partly broken away of one of the hollow grate elements.

Fig. 5 is a side view of a plurality of the shaker elements arranged in operative relation with an adjacent hollow grate element and indicating the position of a spacing element in relation thereto.

Fig. 6 is a transverse sectional view of a plurality of adjacent hollow grate elements and interposed shaker element to indicate the relation between the same particularly with reference to the distribution of the forced draft supplied by means of the former.

Fig. 7 is a detail view of a crown or twyer plate showing the under side thereof.

Fig. 8 is a similar view of one of the clean out trap doors.

Fig.9 is a similar view of one of the spac ing elements disposed between the hollow grate elements.

Fig. 10 is a similar view of one of the shaker elements.

Essentially the grate consists of a plurality of hollow grate bars or elements 20 constituting means for introducing a forced draft to the fire bed, interspersed with shaker grate bars 21, said hollow grate bars, which are preferably stationary, being arranged alternately with the shaker-bars,

it being understood that changes each of which consists of a plurality of shaker elements fulcrumed in series between and preferably separated by the hollow stationary bars and capable of movement to the extent sufficient to effectively dislodge and remove ashes and clinkers deposited upon the surfaces thereof, the hollow stationary bars having transversely arched crowns so as to facilitate the movement of ashes and clinkers toward the vertical planes of the shaker bars on either side thereof.

The hollow grate bar is preferably in the form of. an open topped box or trough, formed of a casting with an air inlet opening 22 at or near one end thereof, preferably the rear end, and a clean out trap 23 at or near the other end thereof and fitted with a trap door or closure at pivoted as at 25 and having at an intermediate point a depending arm 26 by means of which the trap may be opened to permit the draft of air traversing the interior of the bar to remove therefrom any fine ashes which may find access thereto through narrow transverse twyer openings 27 formed in the twyer plate 28 by which the top of the bar is closed and which plate constitutes the crown of the bar. Said twyer plates are preferably formed in sections so as to permit of placement of portions thereof as may be required in repair, and these sections may be made of any convenient lengths, and

hence are adaptable to furnaces having grate bars of different lengths, being snugly fitted at their edges to the walls of the box forming the body-portion of the bar or air conducting and distributing medium, and also being provided with depending lugs 29 so as to insure the proper positions of the sections with relation to the walls of the box. The air inlet openings are preferably extended to form collars 30 having interlocking or beveled joint connections with complementary collars 31 on the draft box 32 to which the forced draft is supplied, obviously by any suitable means, not illustrated herein and forming no part of the present invention and the slotted formation of the air box constituting the body portions of the hollow grate bars, and the character of the joints employed between the elements by which the forced draft is conveyed thereto serve as means of preventing leakage of air pressure and the discharge of the draft wholly through the twyer openings of the crown or twyer plates, and in this connection it should be noted that the doors or closures with which the clean out traps are fitted are mounted to open inwardly or in opposition to the air pressure within the hollow grate bars, so as to provide against" leakage or waste of pressure at those points. The arrangement of the depending arms 26 at intermediate points in the lengths of the trap doors or closures 24 further insures the tight closing of said doors except when positively moved for clean out purposes, to which end the said arms may be connected near their lower extremities by a transverse rod 33 with which may be connected a suitable operating rod 34 extended to a conveniently accessible point at the front of the furnace. Lugs 35 provided at the front end of the hollow grate bars serve as means for engagement with an eye beam or bearing bar 36 which may form a part of the frame work of the furnace.

The hollow grate bars are held in the desired relative positions at the proper interval to permit of the necessary freedom of movement of the shaker elements disposed in series therebetween by means of spacers 37 consisting of hollow blocks resting upon lugs 38 formed on the side walls of the air box and secured by transverse bolts 39 or the equivalent thereof, and the shaker elements are provided with trunnions 40 mounted in hearings or seats 41 also formed on the exterior surfaces of the side walls of said air boxes and are also provided with operating arms 42 which may be connected in series longitudinally of the grate bars by links or rods 43 each of which is common to a series of shaker elements constituting a shaker bar and adapted to be operated from the exterior of the furnace, at the front, through the medium of an operating bar 44. It will be noted that the spacing blocks are cut away at their inner ends or concave to permit of freedom of swinging movement of the shaker elements disposed adjacent thereto while preserving the substantial continuity of the shaker bar when the elements are in theirnormal positions, and the grate is preferably sloped upward near the frontof the furnace to bring the bottoms of the grate bars substantially on a level with the bottom of the fire door, not only to facilitate the use of a slice bar when required, but also to serve as a guide to the fireman in regulating a light bed of fuel by maintaining the fire on a level with the bottom of the door. As before indicated, the clean out traps are preferably located at the front ends of the hollow grate bars so that the ashes discharged therefrom when open may be deposited in the ash pit within convenient reach for removal andthe edges of the trap doors or closures are beveled-to insure tight joints when the same are closed.

The purpose of arching the crown plates of the hollow grate bars is not only as above noted, to cause ashes and clinkers deposited thereon to slide laterally to within reach of the elements of the shaker bars, but also to serve as a means of distributing or spreading columns of air discharged through the twyer openings, as indicated by the darts in Fig. 6, so that the upwardly spreading columns of air from adjacent grate bars intersect above the plane of the grate and relatively close to the surface thereof, so that there is but a small space above each shaker grate bar to be supplied with air by the natural draft entering through the shaker grate bars, supplemented, however, by the suction or introduced current incident to the relatively rapid movement of the columns of air rising from the forced draft bars, and therefore in practice a substantial uniform supply of air to all parts of the fire bed is maintained and a correspondingly uniform combustion is effected and may be regulated in rapidity, to produce the desired results so far as steam production is concerned by regulations of the intensity of the forced draft which is supplied.

The invention having been described, what is claimed as new and useful is:

1. A combined forced draft and natural draft shaker grate comprising alternately arranged hollow and shaker grate bars, the former being provided with crowns having twyer openings and the latter consisting of series of independently movable elements having trunnions mounted in bearings on the side walls of the hollow bars, means respectively for supplying a forced draft to the hollow bars, and means for operating said shaker bars.

2. A combined forced draft and natural draft shaker grate comprising alternately arranged hollow and shaker grate bars, spacer blocks secured between the hollow bars in the vertical planes of the shaker bars, said hollow bars being provided with crowns having twyer openings and the shaker grate bars consisting of series of independently movable shaker elements having trunnions mounted in bearings on the side walls of the hollow bars and provided with depending operating arms, means for connecting said operating arms in series for simultaneous movement, and means for supplying a forced draft to the hollow bars.

3. A combined forced draft and natural draft shaker grate comprising alternately arranged hollow and shaker grate bars, said hollow bars being provided with crowns and having twyer openings, the shaker bars consisting of series of independently movable shaker elements having trunnions mounted in bearings on the side walls of the hollow bars and provided with depending operating arms, links pivotally secured to the lower end of said arms and connecting the shaker elements in series longitudinally of the hollow bars, whereby all the elements of the shaker bars may be moved simultaneously, and means for supplying a forced draft to the hollow bars.

4. A combined forced draft and natural draft shaker grate comprising alternately arranged hollow and shaker grate bars, spacer blocks secured between the hollow bars in the vertical planes of the shaker bars, said hollow bars being provided with crowns having twyer openings, the shaker bars consisting of series of independently movable shaker elements having trunnions, the hollow bars on the exterior side walls thereof being provided with bearing seats for said trunnions, the seats being open at the tops whereby the said trunnions may be disengaged from the seats, the said elements being provided with depending operating arms, means serially connecting the elements of each shaker bar so that they may be moved in unison, and means for supplying a forced draft to the hollow bars.

In testimony whereof we affix our signatures.

WILLIAM S. HOTCHKISS. JOHN E. W. SHEEHAN. 

